Problems with the Foreach Loop array

Problems with the Foreach Loop array
The $account array is as follows
Array
(
[Tencent] = = Array
(
[0] = mylove_fish2008
[1] = Caochengli_love
)

[Sina] = = Array
(
[0] = 2935994540
[1] = 3177446321
)

[163] = = Array
(
[0] = 3395157578
[1] = 8589895537
)

[Sohu] = = Array
(
[0] = 1400582280
[1] = 1044720542
)

)

I'm going to loop this array now, there are two ways
1.foreach ($account as $key = $rows)
{
foreach ($rows as $val)
{
echo $val. ";
}
}

2.foreach ($account [' Tencent '] as $val)
{
echo $val. ";
}
$account [' Sina '], $account [' 163 '], looping like $account [' Sohu ']

Loop the two-dimensional array, which is the high efficiency

------Solution--------------------
References:

Reference: Set your two-dimensional array contains n one array, one-dimensional array has m key values,
So complete the traversal example 1 time complexity
For O (n*m)
Example 2
O (m+m+m) (N) = "O (n*m)
Efficiency I think it should be the same.

Two loops
$t 1 = microtime (true);
$data = Array (' tencent ' =

...
Indeed, as the landlord said, the browser under example 2 of the efficiency ratio of 1 faster nearly a time, but I think the landlord gave example 1 test cases
$t 1 = microtime (true);
$data = Array (' tencent ' = = Array (' CADFDG ', ' dfdgg '), ' sina ' = = Array (' 111 ', ' 4654654 '));
Position should be swapped
Here's my test code.

 
 Class Runtime {
 Public $StartTime = 0; 
 Public $StopTime = 0;      
 
 Function Get_microtime () {
 List ($usec, $sec) = Explode ("', Microtime ());   
 Return (float) $usec + (float) $sec);   
} 
 
 Function Start () {
 $this->starttime = $this->get_microtime ();   
} 
 
 Function Stop () {
 $this->stoptime = $this->get_microtime ();     
} 
 
 Function spent () {
 return round (($this->stoptime-$this->starttime) * 1000, 4); 
 